Magnetic amplifier drive for coincident current switch



Aug. 25, 1959 v J. D. LAWRENCE, JR

MAGNETIC AMPLIFIER DRIVE ECR CCINCIDENT CURRENT SWITCH Filed April 29,1955 AGENT United States Patent() MAGNETIC AMPLIFIER DRIVE FORCOINCIDENT CURRENT SWITCH Joseph D. Lawrence, Jr., Philadelphia, Pa.,assignor, by mesne assignments, to Sperry Rand Corporation, New York,N.Y., a corporation of Delaware Application April 29, 1955, Serial No.504,916

14 Claims. (Cl. 340-174) This invention relates to coincident currentswitches. Switches of this type are well known in the prior art but theynormally had a drive system utilizing vacuum tubes kas the principalcomponents thereof. There are a number of disadvantages inherent in thevacuum tube type of drive and it is the primary object of this inventionto overcome these disadvantages.

I Another object of the invention is to provide a coincident currentswitch together with a drive -therefor which is an improvement over theprior art arrangements in the same class.

lt is another object of the invention to providea coincident currentswitch with a drive system of such character that the output pulses ofthe two drive elements producing the coincidence are accurately timedwith respect to each other.

A further obiectvof the invention is to provide a coincident currentswitch adaptedto be connected in a complete overall computing or datatranslating system'where 'eration than prior devices of this character.

Other objects and advantages of the invention will become apparent asthis description proceeds.v

The invention employs a plurality of horizontal lines each controlled,by a magnetic amplifier and a plurality of vertical lines each alsocontrolled by a magnetic amplifier. At each intersection of a horizontaland vertical line there is a core which is magnetized by currents owingin the horizontal and vertical lines. There is a bias winding on thecore. which normally biases the core to negative saturation. If the coildue to the horizontal line but not the coil due to the vertical line (orvice versa) on the core is energized, it will neutralize the biaswinding but the core will remain negatively magnetized. However, if boththe horizontal and the vertical lines passing through a given core areenergized, the bias will be overcome and the core will be switched topositive saturation. There is an output coil on the core in which`potential is induced whenever the core is switched from negative topositive magnetization or Vice versa. The important novelty of theinvention resides in the magnetic ampliiier drive` for the horizontaland vertical lines. Each horizontal line and each vertical line has itsown mag- "n'etie' amplifier controlled by its own input so that upon theselection of a given line the magnetic amplifier will ,Y 2,901,735Patented Aug. 25, 1959 zontal line and a given vertical line are both tobe energized, their output pulses will occur simultaneously. By virtueof the magnetic amplifier type of drive,-the aforesaid objects can beachieved.

In the drawings:

Figure 1 is a schematic diagram of one embodiment of the invention.

Figure 2 illustrates one of the cores together with the coils thereon.

Figure 3 s a hysteresis loop for the core material of Figure 2.

Figure 4 is a timing diagram for the square wave alter` nating currentgenerators PP-l and PP-2 of Figure 1.

In Figure l there is a plurality of horizontal lines H and a pluralityof vertical lines V. At each crossover there is a core v10. Eachhorizontal line is a series circuit and includes the coil H on each core10 of a horizontal row.v Likewise each vertical line is a series circuitand includes the coil V on each core 10 of a vertical column. There is abias winding B on each core 10 and the bias windings are all connectedin series with each other and with a source of bias 29. An outputwinding O on each core may have a rectifier 28 in series therewith ifonly unidirectional output signals are desired.

vThe rectier 28 may, of course, be omitted.

Each vertical line has a driving magnetic amplier all of which have beenshown schematically but only one of which has reference numbers thereon.The explanation of this one applies to all. The output coil 11 of themagnetic amplifier is in series with its complementary vertical line andlis on a core 9 whose hysteresis loop is substantially rectangular.Power winding 12 on the core is in series with source PP-l whichgenerates a square wave alternating current as shown in Figure 4. Thereis also a signal winding 13 which is in series with the square .wavealternating current source PP-Z. As shown in Fgure 4, generator PP-2goes positive during the negative excursions of source PP-l. Due torectifier 27, only the positive excursions of source PP-2 may flowthrough rcoil .13 is grounded through any suitable switch 18 or otherelectrical circuit. This causes the next positive excursion of sourcePP-Z to drive current through coil 13. This resets the core 9 tonegative remanence. During the next positive excursion of source PP-l apositive pulse .will flow through coil 12 Iand drive the core back topositive remanence. This latter action will cause aprapid change in theflux of core 9 and therefore induce a potential in coil 11. Thispotential is in proper polarity to flow through rectifier 26 to thevertical coils V on each of the cores 10 of the second vertical line ofcores. As has already been pointed out, this `action alone is not enoughto induce potentials in the output coils O of the cores 10 of the secondvertical line. This follows from the fact that the bias current throughthe bias coils B has not only saturated this core negatively but hasapplied a very large negative bias of a magnitude illustrated by thevector 30 of Figure 3. The llow of current through the vertical coils Von the cores 10 will exactly counteract the large negative bias 30 andwill return the cores'l to negative remanence. But this still does notinduce potential in the output coils O as the change of llux is verysmall when the core moves from negative saturation asomar lto negativeremanence, as would be the case here. It follows that all of the coresof the selected vertical line stand at negative remanence except for theone which is in the selected horizontal line. If it now be assumed thatthe fifth horizontal line from the top is the selected horizontal line,it is noted that it has an input coil 16 in series with source PP-Z. Ithas an output coil 14 in series with rectifier 17 as well as in serieswith the fifth horizontal line. The power winding 15 is in series withsource PP-l. If the coil 16 were grounded either "through a simpleswitch or any complex piece of electronic equipment, and if thisgrounding occurred at approximately the same time that the free end ofcoil 13 .was grounded, it is noted that the same positive excursion ofsource PP-Z which reset the core 9 will also ow through coil 16 andreset the core 25 to negative remanence. The next positive excursion ofsource PP-l will -ow through coil 15 and drive the core 25 back topositive remanence, whereby there is a large rate of change of flux incore 25 and a large induced potential in coil 14. This potential is inproper direction to drive current Zthrough rectifier 17 and thencethrough the fifth horizontal line including all of the coils H on thecores 10 of that horizontal line. Therefore, the particular core 23which happens to be in both the selected vertical line and the selectedhorizontal line, will have currents flowing in coils H and V thereon andsince both of these currents are substantially equal and opposite to thebias current flowing in coil B, the bias current is more than overcomeand the core is driven rapidly to positive saturation. In going fromnegative to positive saturation it passes across an unsaturated portionof the hysteresis loop and therefore there is a rapid change of fiuxwhich induces a large output potential in the output coil O. The cores9, 10 and 25 hereinabove mentioned, as well as all of ,the other cores,preferably, though not necessarily, should be of any well known materialwhich gives a substantially rectangular hysteresis loop. Examples ofsuitable materials are Orthonik and 4-79 Moly-Permalloy.

In summary, it is clear that an output signal from any desired one ofthe numerous output coils O can be produced by substantiallyconcurrently energizing the inputs Vof the magnetic amplifiers thatrespectively feed the horizontal and vertical lines which cross-over atthe core for the selected output coil O.

I claim to have invented:

1. In a coincident current switch, a core of magnetic material, biasingmeans for applying a biasing magnetizing force to the core in onedirection, an output winding on the core, a first magnetic amplifier,core magnetizing means responsive to the output or" the first magneticamplifier for applying a magnetizing force to the core in a directionopposite to that of the biasing means, a second magnetic amplifier, andcore magneticing means responsive to the output of the second magneticamplifier for applying a magnetizing force to the core in a directionopposite to that of said biasing means, each of said first and secondmagnetic amplifiers having an input winding and a power winding, a firstsource of power pulses coupled to the power windings of both said firstand second amplifiers whereby said amplifiers are energized by saidfirst source in synchronism with one another, a second source of controlpulses, and means for selectively coupling pulses from said secondsource to the input windings of said first and second amplifiers wherebyinput signals are selectively applied to said amplifiers from saidsecond source in synchronism with one another, each of said amplifiersincluding means responsive to an input signal applied thereto forproducing an output.

2. A coincident current switch comprising a first group of magneticamplifiers each having control means4 for controlling the output of theamplifier, a group of cores for each of said first magnetic amplifiers,each of said first magnetic amplifiers having output means forselectively applying a magnetizing force to each core of the groupassociated with said amplifier, a second group of .4 magnetic amplifierseach having control means for controlling the output of the amplifier,each magnetic amplifier of the second group having output means forselectively applying to a group of said cores a magnetizing forceadditive to any magnetizing force applied by said first amplifiers, eachof said first and second magnetic amplifiers including a power windingthereon, means interconnecting the power windings of said first andsecond groups of magnetic amplifiers, a source of spaced energizingpulses coupled to said interconnected power windings whereby theamplifiers in both said first and second groups are energized insynchronism with one another by pulses from said source thereby tosynchronize the selective outputs of said first and second amplifiers,means for applying a biasing magnetizing force to all of said cores in adirection opposing all of the previously mentioned magnetizing forces,said biasing magnetizing force being of such magnitude that each coreremains in a saturated region of its hysteresis loop unless at least twoof said additive synchronized magnetizing forces are applied to it inwhich event it will move along an unsaturated portion of its hysteresisloop thereby effecting a substantial rate of change of flux in the core,each core having an output winding thereon in which potential is inducedwhen the flux therethrough changes.

3. A coincident current switch as defined in claim 2 in which eachmagnetic amplifier includes, in addition to said power winding, a coreof magnetic material exhibiting a substantially rectangular hysteresisloop, an output coil on the core, and a control winding on the core.

4, A coincident current switch comprising a plurality of horizontallines, a plurality of vertical lines which cross all of the horizontallines, a core at each crossover, means in each horizontal line forapplying a magnetizing force to each core along the line, means in each/ertical line for applying a magnetizing force additive to anypreviously recited magnetizing force to each core along the line, arectifier in each horizontal line, a rectifier in each vertical line,means for applying normal potentials to all of the rectifiers to biasthem to cut off, a magnetic amplifier in each horizontal line, amagnetic amplifier in each vertical line, pulse generator means forapplying power pulses synchronously to all the magnetic amplifiers, eachmagnet amplifier having control means to control its output andincluding means whereby when its control means is controlled to effect apulse output from the amplifier that a pulse appears on the lineassociated with the amplifier and overcomes the bias on the rectifier inthat line so as to cause a fiow of current in the line to thereby applymagnetizing forces to all of .the cores associated with that particularline, and biasing magnetizing means for applying a biasing magnetizingforce to all of said cores in a direction opposite the previouslymentioned magnetizing forces and of such magnitude as to drive the coresto saturation region eX- cept when at least two of said additivemagnetizing forces -concurrently are applied to a core in which latterevent the core will be driven from said saturation region along anunsaturated portion of its hysteresis loop, and output means associatedwith each core responsive to the changes of flux therein.

5. A coincident current switch as defined in claim 4 in which eachmagnetic amplifier has a core, an output coil on the core in series withits associated line, a control winding on the core, and a power windingconnected to said pulse generator means.

6. A coincident current switching system comprising a plurality ofhorizontal lines, a plurality of vertical lines each of which crossesall of the horizontal lines, a core at each cross-over, means in eachhorizontal line for applying a magnetizing force to each core along theline, means in each vertical line for applying a magnetizing forceadditive to any previously recited magnetizing force to each core alongthe line, a rectifier in each horizontal line, a rectifier each verticalline', 'means for applying nll p'tentials' t0 all 0f- 'Said TCe'Sibla'sihei t0 Cut off, a magnetic amplifier in each horizontal line, amagnetic amplifier in each vertical line, each magnetic amplifier havinga core with control, power and output windings thereon, rst pulse meanscoupled to each of said power windings for supplying spaced synchronizedpulses to each of said powerwindings, second pulse means for applyingsynchronized control pulses to selected ones of said control windingsduring-the spaces between the first-named pulses, and biasingmagnetizing means for applying a biasing magnetizing force to all ofsaid cores in a direction opposite to the previously mentionedmagnetizing forces and of such magnitude as to drive the core tosaturation region except when at least two of said additivc magnetizingforces concurrently are applied to a core in which latter event the corewill be driven from said saturation region along an unsaturated portionof its hysteresis loop, and output means responsive to the conditions ofthe cores.

7. A coincident current switch as defined in claim 6 in which the outputmeans includes a coil on each core.

8. In combination, a plurality of magnetic cores, a first group of drivelines coupled to said cores in a first orientation, a second group ofdrive lines coupled to said cores in a second orientation, each of saidcores being responsive to simultaneous drive on drive lines coupledthereto in both said orientations and being substantially non-responsiveto drive on drive lines coupled thereto in one only of saidorientations, and means for selecting lines and for effectingsynchronized drive on selected lines in both said orientationscomprising a first group of pulse-type magnetic amplifiers havingoutputs coupled respectively to said first group of drive lines, asecond group of pulse-type magnetic amplifiers having outputs coupledrespectively to said second group of drive lines, each of saidamplifiers in said first and second groups of amplifiers having meansfor applying input signals to said amplifier a power winding forapplying power energization to said amplifier, means interconnecting thepower windings of each of said groups of amplifiers to one another andto the power windings of the other group of amplifiers, and a source ofspaced power pulses coupled to said interconnected power windings forsynchronously energizing the power windings of both said first andsecond groups of amplifiers.

9. The combination of claim 8 wherein the power windings of said firstand second amplifier groups are connected in series with one another.

10. In combination, a plurality of magnetic cores, a first group ofdrive lines coupled to said cores in a first orientation, a second groupof drive lines coupled to said cores in a second orientation, each ofsaid cores being responsive to simultaneous drive on drive lines coupledthereto in both said orientations and being substantially non-responsiveto drive on drive lines coupled thereto in one only of saidorientations, and means for selecting lines and for effectingsynchronized drive on selected lines in both said orientationscomprising a first group of pulse-type magnetic amplifiers havingoutputs coupled respectively to said first group of drive lines, asecond group of pulse-type magnetic amplifiers having outputs coupledrespectively to said second group of drive lines, each of saidamplifiers in said first and second groups of amplifiers having a powerwinding for applying power energization to said amplifier, meansinterconnecting the power windings of each of said groups of amplifiersto one another and to the power windings of the other group ofamplifiers, a source of spaced power pulses coupled to saidinterconnected power windings for synchronously energizing the powerwindings of both said first and second groups of amplifiers an inputwinding on each of said ampliers for controlling the output of saidamplifier, a further source of pulses producing pulses in the spacesbetween said spaced power pulses,

'6 and control means for coupling pulses from said further pulse sourceto selected ones of said input windings, whereby said selected inputwindings are synchronously controlled by input pulses occurring betweenthe times of occurrence of said spaced'power pulses.

ll. In combination, a plurality ofmagneticcores, a first group of drivelines coupled to said cores in a first orientation, a second' group ofdrive lines coupled to said cores in a second orientation, each of'saidcores being responsive to simultaneous drive on drive lines coupledthereto in both saidorientat-ions' and being substantiallynon-responsive to drive on drive lines coupled thereto in one only ofsaid orientations, and means for selecting lines and for effectingsynchronized drive on selected lines in both said orientationscomprising a first group of pulse-type magnetic amplifiers havingoutputs coupled respectively to said first group of drive lines, asecond group of pulse-type magnetic amplifiers having outputs coupledrespectively to said second group of drive lines, each of saidamplifiers in said first and second groups of amplifiers having a powerwinding for applying power energization to said amplifier, meansinterconnecting the power windings of each of said groups of amplifiersto one 'another and to the power windings of the other group ofamplifiers, a source of spaced power pulses coupled to saidinterconnected power windings for synchronously energizing the powerwindings of both said rst and second groups of amplifiers an inputwinding on each of said ampliers for controlling the output of saidamplifiers, a further source of pulses producing pulses in the spacesbetween said spaced power pulses, and control means for coupling pulsesfrom said further pulse source to selected ones of said input windings,whereby said selected input windings are synchronously controlled byinput pulses occurring between the times of occurrence of said spacedpower pulses, said control means including means for connecting selectedones of said input windings in parallel across said further source ofpulses.

l2. In combination, a plurality of magnetic cores, a first group ofdrive lines coupled to said cores, a second group of drive lines coupledto said cores, each of said cores having a drive thresholdcharacteristic which is exceeded by simultaneous` drive from both saidgroups and which is greater than a drive from one only of said groups,and means for selecting a drive line from each of said groups and fordriving synchronously selected lines in both of said groups, saidselecting and driving means comprising a first group of pulse-typemagnetic amplifiers having outputs coupled respectively to said firstgroup of drive lines, a second group of pulse type magnetic amplifiershaving outputs coupled respectively to said second group of drive lines,each of said amplifiers in said first and second groups of amplifiershaving a power winding coupled to the amplifier output, and an inputwinding for controlling the output drive of said amplifier, meansinterconnecting the power windings of each of said groups of amplifiersto one another and to the power windings of the other group ofamplifiers, and a source of spaced power pulses coupled to saidinterconnected power windings for synchronously energizing the powerwindings of both said first and said second groups of amplifiers.

13. The combination of claim l0 and further including a further sourceof pulses producing other pulses in the spaces vbetween said spacedpower pulses, and control means for coupling said further pulse sourceto selected ones of said input windings, whereby said selected inputwindings are synchronously energized by said other pulses.

14. In combination, a plurality of cores each of which comprisesmagnetic material capable of assuming stable remanence conditions, meansfor applying a biasing magnetizing force to said cores in a rstdirection, and means for applying a magnetizing force to said cores in adirection opposite to that of said biasing force, said force applyingmeans comprising first and second pluralities of idrivelines coupled tosaid cores, one drive line from each of said rst and second pluralitiesbeing coupled to each core, rst and second pluralities of magneticampliers coupled respectively to said first and second pluralities ofdrive lines, each of said amplifiers including an input winding and apower winding, a source of control -pulses, means for selectivelytranslating pulses from said vcontrol pulse source to the input windingsof said ampli- ,iiers so that input pulses are applied to selected onesof said irst and second pluralities of amplifiers in synchronism withone another, and a source of power pulses V8 coupled to all of saidpower windings so that the ampli; ers are energized by said power pulsesource in synchronism with one another.

' References Cited in the le of this patent UNITED STATES PATENTS2,709,248 Rosenberg May 24, 1955 2,734,184 Rajchman Feb. 7, 1956 102,734,187 Rajchman Feb. 7, 1956 UNITED STATES PATENT OFFICE CERTIFICATEOE CORRECTION Patent Noo 2,901,735 August 25, 1959 Joseph D., Lawrence,Jr.,

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 3, line 53, for "magnetieing" read magnetizing Column 4, line 44,forv "magnet amplifier" read M- magnetie amplifier mx; column 6, lineI63, for the Claim reference numeral "lO" read e l2 nu.,

Signed and sealed this 29th day of March l960o (SEAL) Attest:

KARL H., AXLINE ROBERT C. WATSON Attesting OHcer Commissioner of Patents

